[PATCH v4 12/17] KVM: Move x86's perf guest info callbacks to generic KVM

[Sean Christopherson <seanjc@google.com>]

Move x86's perf guest callbacks into common KVM, as they are semantically
identical to arm64's callbacks (the only other such KVM callbacks).
arm64 will convert to the common versions in a future patch.

Implement the necessary arm64 arch hooks now to avoid having to provide
stubs or a temporary #define (from x86) to avoid arm64 compilation errors
when CONFIG_GUEST_PERF_EVENTS=y.

Acked-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/arm64/include/asm/kvm_host.h | 10 ++++++
 arch/arm64/kvm/arm.c              |  5 +++
 arch/x86/include/asm/kvm_host.h   |  3 ++
 arch/x86/kvm/x86.c                | 53 +++++++------------------------
 include/linux/kvm_host.h          | 10 ++++++
 virt/kvm/kvm_main.c               | 44 +++++++++++++++++++++++++
 6 files changed, 83 insertions(+), 42 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 5a76d9a76fd9..72e2afe6e8e3 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -678,6 +678,16 @@ int io_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa);
 void kvm_perf_init(void);
 void kvm_perf_teardown(void);
 
+/*
+ * Returns true if a Performance Monitoring Interrupt (PMI), a.k.a. perf event,
+ * arrived in guest context.  For arm64, any event that arrives while a vCPU is
+ * loaded is considered to be "in guest".
+ */
+static inline bool kvm_arch_pmi_in_guest(struct kvm_vcpu *vcpu)
+{
+	return IS_ENABLED(CONFIG_GUEST_PERF_EVENTS) && !!vcpu;
+}
+
 long kvm_hypercall_pv_features(struct kvm_vcpu *vcpu);
 gpa_t kvm_init_stolen_time(struct kvm_vcpu *vcpu);
 void kvm_update_stolen_time(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index f5490afe1ebf..93c952375f3b 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -496,6 +496,11 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
 	return vcpu_mode_priv(vcpu);
 }
 
+unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)
+{
+	return *vcpu_pc(vcpu);
+}
+
 /* Just ensure a guest exit from a particular CPU */
 static void exit_vm_noop(void *info)
 {
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 812c08e797fe..ec16f645cb8c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1565,6 +1565,9 @@ static inline int kvm_arch_flush_remote_tlb(struct kvm *kvm)
 		return -ENOTSUPP;
 }
 
+#define kvm_arch_pmi_in_guest(vcpu) \
+	((vcpu) && (vcpu)->arch.handling_intr_from_guest)
+
 int kvm_mmu_module_init(void);
 void kvm_mmu_module_exit(void);
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e9e1a4bb1d00..bafd2e78ad04 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8410,43 +8410,12 @@ static void kvm_timer_init(void)
 			  kvmclock_cpu_online, kvmclock_cpu_down_prep);
 }
 
-static inline bool kvm_pmi_in_guest(struct kvm_vcpu *vcpu)
-{
-	return vcpu && vcpu->arch.handling_intr_from_guest;
-}
-
-static unsigned int kvm_guest_state(void)
-{
-	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
-	unsigned int state;
-
-	if (!kvm_pmi_in_guest(vcpu))
-		return 0;
-
-	state = PERF_GUEST_ACTIVE;
-	if (static_call(kvm_x86_get_cpl)(vcpu))
-		state |= PERF_GUEST_USER;
-
-	return state;
-}
-
-static unsigned long kvm_guest_get_ip(void)
-{
-	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
-
-	/* Retrieving the IP must be guarded by a call to kvm_guest_state(). */
-	if (WARN_ON_ONCE(!kvm_pmi_in_guest(vcpu)))
-		return 0;
-
-	return kvm_rip_read(vcpu);
-}
-
 static unsigned int kvm_handle_intel_pt_intr(void)
 {
 	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
 
 	/* '0' on failure so that the !PT case can use a RET0 static call. */
-	if (!kvm_pmi_in_guest(vcpu))
+	if (!kvm_arch_pmi_in_guest(vcpu))
 		return 0;
 
 	kvm_make_request(KVM_REQ_PMI, vcpu);
@@ -8455,12 +8424,6 @@ static unsigned int kvm_handle_intel_pt_intr(void)
 	return 1;
 }
 
-static struct perf_guest_info_callbacks kvm_guest_cbs = {
-	.state			= kvm_guest_state,
-	.get_ip			= kvm_guest_get_ip,
-	.handle_intel_pt_intr	= NULL,
-};
-
 #ifdef CONFIG_X86_64
 static void pvclock_gtod_update_fn(struct work_struct *work)
 {
@@ -11153,9 +11116,11 @@ int kvm_arch_hardware_setup(void *opaque)
 	memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops));
 	kvm_ops_static_call_update();
 
+	/* Temporary ugliness. */
 	if (ops->intel_pt_intr_in_guest && ops->intel_pt_intr_in_guest())
-		kvm_guest_cbs.handle_intel_pt_intr = kvm_handle_intel_pt_intr;
-	perf_register_guest_info_callbacks(&kvm_guest_cbs);
+		kvm_register_perf_callbacks(kvm_handle_intel_pt_intr);
+	else
+		kvm_register_perf_callbacks(NULL);
 
 	if (!kvm_cpu_cap_has(X86_FEATURE_XSAVES))
 		supported_xss = 0;
@@ -11184,8 +11149,7 @@ int kvm_arch_hardware_setup(void *opaque)
 
 void kvm_arch_hardware_unsetup(void)
 {
-	perf_unregister_guest_info_callbacks(&kvm_guest_cbs);
-	kvm_guest_cbs.handle_intel_pt_intr = NULL;
+	kvm_unregister_perf_callbacks();
 
 	static_call(kvm_x86_hardware_unsetup)();
 }
@@ -11776,6 +11740,11 @@ bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
 	return vcpu->arch.preempted_in_kernel;
 }
 
+unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)
+{
+	return kvm_rip_read(vcpu);
+}
+
 int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 {
 	return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 60a35d9fe259..da843044e0c1 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1162,6 +1162,16 @@ static inline bool kvm_arch_intc_initialized(struct kvm *kvm)
 }
 #endif
 
+#ifdef CONFIG_GUEST_PERF_EVENTS
+unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu);
+
+void kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void));
+void kvm_unregister_perf_callbacks(void);
+#else
+static inline void kvm_register_perf_callbacks(void *ign) {}
+static inline void kvm_unregister_perf_callbacks(void) {}
+#endif /* CONFIG_GUEST_PERF_EVENTS */
+
 int kvm_arch_init_vm(struct kvm *kvm, unsigned long type);
 void kvm_arch_destroy_vm(struct kvm *kvm);
 void kvm_arch_sync_events(struct kvm *kvm);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3f6d450355f0..75d32fc031b5 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -5479,6 +5479,50 @@ struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void)
         return &kvm_running_vcpu;
 }
 
+#ifdef CONFIG_GUEST_PERF_EVENTS
+static unsigned int kvm_guest_state(void)
+{
+	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
+	unsigned int state;
+
+	if (!kvm_arch_pmi_in_guest(vcpu))
+		return 0;
+
+	state = PERF_GUEST_ACTIVE;
+	if (!kvm_arch_vcpu_in_kernel(vcpu))
+		state |= PERF_GUEST_USER;
+
+	return state;
+}
+
+static unsigned long kvm_guest_get_ip(void)
+{
+	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
+
+	/* Retrieving the IP must be guarded by a call to kvm_guest_state(). */
+	if (WARN_ON_ONCE(!kvm_arch_pmi_in_guest(vcpu)))
+		return 0;
+
+	return kvm_arch_vcpu_get_ip(vcpu);
+}
+
+static struct perf_guest_info_callbacks kvm_guest_cbs = {
+	.state			= kvm_guest_state,
+	.get_ip			= kvm_guest_get_ip,
+	.handle_intel_pt_intr	= NULL,
+};
+
+void kvm_register_perf_callbacks(unsigned int (*pt_intr_handler)(void))
+{
+	kvm_guest_cbs.handle_intel_pt_intr = pt_intr_handler;
+	perf_register_guest_info_callbacks(&kvm_guest_cbs);
+}
+void kvm_unregister_perf_callbacks(void)
+{
+	perf_unregister_guest_info_callbacks(&kvm_guest_cbs);
+}
+#endif
+
 struct kvm_cpu_compat_check {
 	void *opaque;
 	int *ret;
-- 
2.34.0.rc0.344.g81b53c2807-goog